Matrix arrays of bi-stable semiconductor switching elements have been suggested for use as memory devices. Although these elements are potentially inexpensive and capable of integration, they are difficult to organize into a matrix array without requiring additional components to provide gating during the writing and reading cycles. Also, such matrix arrays often have "sneak paths", with reliability only being assured with the incorporation of still additional circuit components.
Matrix arrays have also been used to detect visible images. U.S. Pat. No. 3,767,928 teaches a far infrared image detector comprised of a two-dimensional array of chalcogenide glass thermistor bolometers which change their electrical conductivity as a function of temperature. If an image or pattern of infrared energy is focused on the array, the intensity of the radiation can be determined or reproduced by measuring the resistance of each bolometer of the array. The infrared imaging array of U.S. Pat. No. 3,767,928 does not provide for refreshing of the image or pattern focused thereon and is not capable of utilization as a memory device.